Improvement in stereoscopes



W. E. LEWIS.

sTEnEoscoPE. N'o.17,0,749. Patented nec. 7, 1875.

, /l ,d wif? 75@ 51 UNITED STATES PATENT OFFICE.

WILLIAM H. LEWIS, OF NEW YORK, N. Y., ASSIGNOR TO' E. AND H. T. ANTHONY 85 CO., OF SAME PLACE.

IMPROVEMENT IN STEREOSCOPES.

Specification forming part of Letters Patent No. 170,749,

dated December 7, 1875; application iled October 20, 1874.

To all 'whom it may concern Be it known that I, WILLIAM H. LEWIS, of the city and State of New York, have invented an Improvement in Stereoscopes, ot' which the following is a specification:

Stereoscopes have been made with a pictureholder sliding longitudinally of the bar forming the base of the stereoscope, and said holder has been provided with a metal spring below the base, that has furnished the means for retaining the picture-holding slide at any position to which it may be moved, the friction of such spring accomplishing this object, but the holder is liable to assume a diagonal position to the bar or base.

My present invention is for the purpose of guiding the picture-holder, so that it will move freely, and always be held at right angles to the bar.

I make use of a groove or rib at the under side of the bar, and the metal spring is made with four arms, two of which are connected with the picture-holder, and the other two run at their ends in or upon the rib or groove at the under side ofthe bar. Thereby the sliding picture-holder is kept in position, but is free to be moved in bringing the picture to focus.

In the drawing, Figure 1 is an inverted plan, and Fig. 2 is a view endwise, of the bar.

The stereoscope-instrnment is of the ordinary character, so far as the glasses a, hood b, division c, and picture-holder d; and the baror base c is of usual construction, except that a groove, c', is made longitudinally thereof in the said bar, or a rib placed thereon, and the spring h is made of four metal arms, 2 2 and 3 3, the former being united to the pictureholder, and the latter having rounded projections running in the groove c', or bent up to grasp the rib, so that the picture-holder is held firmly by the spring at the bearing-points that produce the friction.

Springs have been employed in many ways for producing a yielding frictional resistance, and springs have been placed within grooves.

In my improved stereoscope the ends of the spring become guides for the picture-holder in addition to furnishing the frictional resistance, in consequence ofsuch spring ends resting in a groove or upon a rib, and sliding as the holder is moved.

I claim as my invention- The guide and frictional detainer for the picture-slide of a stercoscope-instrument composed ot' the spring It, that is attached to said slide, and bears at its ends in a groove, or upon a rib at the under side of the bar e, to form a guide, as set forth.

Signed by me this 16th day W. H. LEWIS.

of October,

Witnesses:

GEO. T. PINcKNEY, CEAS. H. SMITH. 

